As the number of users in a wireless network increases and the network application services become more versatile, how to ensure that user equipment (UE) that uses these network application services can have better mobile network quality and transmission rate is becoming one of the concerned topics for a long term evolution technique (LTE) and an advanced long term evolution technique (LTE-A).
The 3rd Generation Partnership Project (3GPP) proposed a wireless network architecture, i.e., the Heterogeneous Network (HetNet), that employs a high-power macro base station (Macro eNB), a low-power pico base station (Pico eNB) and a femto base station (Femto eNB) and can increase the network capacity.
The advanced long term evolution technique further proposed an Enhanced Intercell Interference Coordination (eICIC) that solves the co-channel interference problem between the high-power base station and the low-power base station in the HetNet.
However, in an anti-interference mechanism provided in the eICIC, an almost blank subframe generates abnormal cell-selection behaviors to user equipment that is disposed in a region of a signal range of the base station intersecting with a signal range of the neighboring base station and has a long term evolution technique (LTE).
In other words, the user equipment that has the LET measures the Reference Signal Received Quality (RSRQ) of the base station and the neighboring base station, performs cell-selection according to the RSRQ and a parameter threshold for cell-selection, and decides whether it should handover to the neighboring base station or stay in the original base station according to a result of the cell-selection.
However, since the RSRQ is a ratio of the reference signal received power (RSRP) and the received signal strength indication (RSSI), and an almost blank subframe (ABS) does not need to transmit the data of the base station such that the number of interfering sources becomes smaller, the RSSI measured by user equipment that has the LTE is reduced. As a result, the RSRQ is too optimistic, and the user equipment that has the LTE generates abnormal cell-selection behaviors. Therefore, erroneous handover decisions are made between the service base station and the neighboring base station.
Therefore, how to overcome the above drawbacks is becoming an urgent issue in the art.